IEO Level 2- English Olympiad (SOF) Class 9 Coaching Programs
⏳ 🎯 Online Tests (2 Tests [50 Questions Each]): NTA Pattern, Analytics & Explanations
Click Here to View & Get Complete Material
Rs. 200.00
3 Year Validity (Multiple Devices)
🎓 Study Material (303 Notes): 2024-2025 Syllabus
Click Here to View & Get Complete Material
Rs. 450.00
3 Year Validity (Multiple Devices)
🎯 250 MCQs (& PYQs) with Full Explanations (2024-2025 Exam)
Click Here to View & Get Complete Material
Rs. 200.00
3 Year Validity (Multiple Devices)
Hydrogen and S-Block Element: Physical Properties of Alkali Metals
Physical Properties of Alkali Metals
- As we go down the group the alkali metals show steady increase in size due to the addition of a new shell at each step.
- The increase in size of the atoms or ions, directly influences the physical and chemical properties of the alkali metals.
Some physical properties are given in Table:
Trends in physical properties are listed in Table:
Chemical Properties of Alkali Metals
Oxides
- All alkali metals form oxides, which are basic in nature.
- Lithium forms only one type of oxide, lithium monoxide because Tiny lithium ion is not able to come in contact with sufficient number of per oxo ions.
- Sodium peroxide is formed when sodium is heated with oxygen.
- Other metals of this group also form superoxide՚s on reaction with oxygen.
Reactivity Towards Water
All the metals of this group react with water explosively to form hydroxide and liberate hydrogen.
- The lithium has most electronegative but the reaction with water is considerably less vigorous than that of sodium which has the least negative among the alkali metals.
- The low reactivity of lithium is due to small size and high ionization enthalpy.
Basic character of oxides and hydroxides:
The basic character of oxides and hydroxides of alkali metals increases with the increase in size of metal ion.
Hydrides
The alkali metals react with hydrogen at about to form hydrides , where stands for alkali metals.
Halides
Alkali metals react with halogens to form halides: